Make Django forms.ChoiceField accept choices from a very large data set(see: http://blog.ikraftsoft.com/post/1342312823/)

forms.py

from django import forms
list_of_choices = (
    (1, 'Choice 1'),
    (2, 'Choice 2'),
    (3, 'Choice 3'),
    # ...
    (n, 'Choice n'),
)
class MyForm(forms.Form):
    my_choice_field = forms.ChoiceField(choices=list_of_choices)

forms_updated.py

from django import forms

class LazyChoiceField(forms.ChoiceField):
    def __init__(self, *args, **kwargs):
        super(LazyChoiceField, self).__init__(*args, **kwargs)

    def valid_value(self, value):      
        # your custom validation code for  "value" argument goes here
        # return True if value is valid else return False

list_of_choices = (
    (1, 'Choice 1'),
    (2, 'Choice 2'),
    (3, 'Choice 3'),
    # ...
    (n, 'Choice n'),
)

class MyForm(forms.Form):
    my_choice_field = LazyChoiceField(choices=list_of_choices)